Both matchups are part of the un-aired preliminary card of the Aug. 18 event, which takes place at The Pearl at the Palms Casino Resort in Las Vegas.

The night’s main card, including a championship headliner between bantamweight title-holder Dominick Cruz and top contender Joseph Benavidez, airs on Versus.

Vazquez, a 12-year pro, fought and defeated a fellow MMA trailblazer in his most recent performance. Following a pair of frustrating and razor-thin split-decision losses to L.C. Davis and Deividas Taurosevicius in his first two WEC fights, Vazquez got back in the win column at WEC 47 when he topped Jens Pulver via first-round submission.

His opponent, Semerzier, looks to rebound from his first career loss. In his promotional debut at WEC 43, he pulled off one of 2009’s biggest upsets when he delivered Brazilian jiu-jitsu black belt Wagnney Fabiano the first submission loss of his career. However, he then dropped a unanimous decision to Taurosevicius at WEC 46, and a WEC 48 bout with Anthony Morrison was scratched when Semerzier was forced off the card with an injury.

Lamas, meanwhile, opened his WEC career with a 1-1 mark after earning a March 2009 win over Bart Palaszewski and falling victim to a Danny Castillo TKO in August 2009. Lamas since has bounced back with a unanimous-decision win over James Krause and a devastating knockout of Bendy Casimir at WEC 47 in March.

Jansen looks to bounce back from the first loss of his career after dropping a unanimous decision to Kamal Shalorus at January’s WEC 46 event. Prior to the loss, the M-1 vet carried a 14-fight win streak into his WEC debut this past October at WEC 43 and earned a decision victory over Richard Crunkilton.

The latest WEC 50 card now includes:

MAIN CARD

Champ Dominick Cruz vs. Joseph Benavidez (for bantamweight
title)

Urijah Faber vs. Takeya Mizugaki

Scott Jorgensen vs. Brad Pickett*

Anthony Pettis vs. Shane Roller

Chad Mendes vs. Cub Swanson*

PRELIMINARY CARD

Zach Micklewright vs. Bart Palaszewski

Maciej Jewtuszko vs. Anthony Njokuani*

Mackens Semerzier vs. Javier Vazquez

Dave Jansen vs. Ricardo Lamas

Bryan Caraway vs. Fredson Paixao

* – Not officially announced

For the latest on WEC 50, stay tuned to the MMA Rumors section of MMAjunkie.com.

As the UFC 189 tour made its last stop in Dublin, featherweight champ Jose Aldo was met with a torrent of abuse from the Irish fans. It might have been unpleasant, but it might also have been just what he needed.